Very thin, fuel-smelling oil and lots of it would indicate a leaking fuel injector. The tank is quite happy to gravity feed through the pump to the fuel rail, and if an injector is stuck open it can allow a quantity of fuel to drain into a cylinder, past the rings and into the crankcase. Good thing that you changed that out promptly, bad things can happen with so much fluid in the crankcase, and you likely have ejected some excess oil up to the airbox through the crankcase breather, which might explain a bit of smoke. Open the airbox up and take a look, a little oil mist is normal but not much in liquid form.